Powder corrosion and chip-resistant coating

ABSTRACT

A powder composition including a resin and from 5% to 70%, by weight based on powder composition weight, of a corrosion-inhibiting pigment, optionally including from 0% to 65%, by weight based on powder composition weight, zinc, the composition being substantially free from pigment providing a metallic effect is provided. The corrosion-inhibiting pigment may be present in amounts of up to 50%, by weight based on powder composition weight, for example, up to 35%. A method for coating a substrate with the powder composition and the coated substrate so formed are also provided.

This application claims the benefit of priority under 35 U.S.C. §119(e)of U.S. Provisional Patent Application No. 61/211, 847 filed on Apr. 3,2009.

This invention relates to a powder composition suitable for powdercoating. More particularly this invention relates to a powdercomposition including a resin and from 5% to 70%, by weight based onpowder composition weight, of a corrosion-inhibiting pigment, thecomposition being substantially free from pigment providing a metalliceffect. This invention also relates to a method for coating a substratewith the powder composition and a coated substrate.

U.S. Pat. No. 7,244,780 discloses powder coating compositions thatcomprise a film-forming polymer, a pigment such as aluminum flakeproviding a metallic effect and a stabilizing additive that inhibitsdegradation of the metallic pigment.

U.S. Pat. No. 7,018,716 discloses corrosion- and chip-resistant coatingsfor high tensile steel components, such as automotive coil springs,formed from a coating powder composition of “toughened” epoxy resin. Ina single coat embodiment, the entire coating is loaded with at least 75phr zinc powder. In a dual coat embodiment, an inner coat is loaded withat least 75 phr zinc and an outer, zinc-free coating is reinforced bythe addition of fibers and/or by a foaming agent which renders itporous.

There has been a need for a powder composition suitable for coating asubstrate, particularly a steel substrate such as, for example, hightensile steel wherein a coating formed from the composition exhibits ahigh level of chip resistance and corrosion resistance without relyingon the use of high levels of zinc metal. The powder composition of thepresent invention is capable of exhibiting a high level of chipresistance and corrosion resistance without relying on the use of highlevels of zinc metal.

In a first aspect of the present invention, there is provided a powdercomposition comprising a resin and from 5% to 70%, by weight based onpowder composition weight, of a corrosion-inhibiting pigment, saidcomposition being substantially free from pigment providing a metalliceffect. The corrosion-inhibiting pigment may be present in amounts of upto 50%, by weight based on powder composition weight, or up to 40%, orup to 35%.

In a second aspect of the present invention there is provided a methodfor coating a substrate comprising: forming a powder compositioncomprising a resin and from 5% to 70%, by weight based on powdercomposition weight, of a corrosion-inhibiting pigment, said compositionbeing substantially free from pigment providing a metallic effect;applying said powder composition to a substrate; and heating said powdercomposition to fuse and cure said applied composition. Thecorrosion-inhibiting pigment may be used in amounts of up to 50%, byweight based on powder composition weight, or up to 40%, or up to 35%.

In a third aspect of the present invention there is provided a methodfor coating a substrate comprising: forming a first powder compositioncomprising a resin and from 0% to 70%, by weight based on powdercomposition weight, of a corrosion-inhibiting pigment, said first powdercomposition being substantially free from pigment providing a metalliceffect; applying said first powder composition to said substrate;forming a second powder composition comprising a resin and from 5% to70%, by weight based on powder composition weight, of acorrosion-inhibiting pigment, said composition being substantially freefrom pigment providing a metallic effect; applying said second powdercomposition to said substrate coated with said first powder composition;and heating said applied powder compositions to fuse and cure saidcompositions. In each of the first and second powder compositions, thecorrosion-inhibiting pigment may be present in amounts of up to 50%, byweight based on powder composition weight, or up to 40%, or up to 35%.

In a fourth aspect of the present invention there is provided a coatedsubstrate comprising said substrate bearing a coating comprising a resinand from 5% to 70%, by weight based on powder composition weight, of acorrosion-inhibiting pigment. The coating may comprisecorrosion-inhibiting pigment in amounts of up to 50%, by weight based onpowder composition weight, or up to 40%, or up to 35%.

The powder composition of the present invention includes at least oneresin, i.e., a polymeric composition suitable for powder coatings suchas, for example, thermoplastic or thermoset resins, particularly anepoxy resin. The epoxy resin may be chosen from a variety of epoxyresins useful for coating powders known in the art, such as thoseproduced by the reaction of epichlorohydrin or polyglycidyl ether and anaromatic polyol such as bisphenol, e.g., bisphenol A. The epoxy resintypically has an epoxy functionality greater than 1.0 and morepreferably greater than 1.9. Generally the epoxy equivalent weightshould be at least 170, but lower values may be acceptable in somecases. Preferably the epoxy equivalent weight is less than 2300, andmore preferably from 800 to 1500. Such epoxy resins may be produced, forexample, by an etherificiation reaction between an aromatic or aliphaticpolyol and epichlorohydrin or dichlorohydrin in the presence of analkali such as caustic soda. The aromatic polyol may be, for example,bis(4-hydroxyphenyl)-2,2-propane (i.e. bisphenol A),bis(4-hydroxyphenyl)-1,1-ethane, bis(4-hydroxyphenyl)-1, 1-isobutane,bis(4-hydroxy-t-butylphenyl)-2,2-propane, bis(2-hydroxynaphthyl)methane,4,4′-dihdyroxybenzophenone or 1,5-pentanediol, 1, 6-hexanediol,diethylene glycol, triethylene glycol, polyethylene glycol,polypropylene glycol or dipropylene glycol, for example diglycidylethers or condensed glycidyl ethers of such diols, can be used. Otheroxirane group-containing polymers that can be used as the epoxy resin inhybrid powder coating compositions according to this invention includepolyglycidyl-functional acrylic polymers or epoxy novolak resins.Preferred epoxy resins for use in the present invention are those basedon bisphenol A.

The powder composition may further incorporate one or more oftoughening, foaming, and reinforcing technologies. “Tougheningtechnology” herein refers to modification of the resin component toprovide a tougher applied coating. “Foaming technology” herein refers topowder compositions selected to engender foam structure in the appliedcoating. “Reinforcing technology” herein refers to additional componentsin the powder composition selected to reinforce the applied coating.

Epoxy resin may be toughened by the use of additives or co-reactantssuch as, for example, as impact modifiers, flexibilizing agents,plasticizers and tougheners. These may include:

-   -   elastomeric modifications, either within the base polymer,        reacted into the coating composition through cross-linking, or        as unreacted additives, such as, for example, CTBN rubber,        butadiene/styrene, nitrile, neoprene, acrylic, butyl,        ethylene/propylene/diene, polysulfide, polyisoprene, silicone,        and urethane rubber;    -   random or block copolymer addition which offer some degree of        internal plastication and may be exemplified by the FORTEGA™        products (Dow Chemical Co.);    -   addition of plasticizers such as epoxidized soybean oil;    -   crosslinked or noncrosslinked core/shell resins with various        compositions such as epoxy, acrylic, polyurethane representing        either the core or the shell portion.

Further, tougheners may include hollow spherical particle includingpolymeric or glass beads.

Discrete microdomains of any of the above may be present and maycontribute to chip resistance.

In one embodiment the epoxy resin, preferably a bisphenol A resin, isadducted to an elastomer having a T_(g) of −30° C. or below, preferably−40° C. or below. The preferred elastomer is CTBN rubber. Suchepoxy/CTBN rubber adducts are described, for example, in U.K. PatentSpecification 1,407,851 (C. G. Taylor) published Sep. 24, 1975 andPowder Coatings, 184 “Elastomer-Modified Epoxy Powder Coatings: aReview”, Apr. 13, 1994, No. 4347. To provide the toughening(flexibilizing) for cold-temperature chip resistance, the CTBN componentshould be present at least 5 wt % of the total of the CTBN and the epoxycomponents. Above about 25 wt % CTBN, no further benefit is realized andit is not desired to exceed 25 wt % lest there be insufficient epoxycomponent for a good cure. The fact that the elastomer component ischemically bound to the epoxy component, i.e., by esterificationreaction of the carboxyl groups of the CTBN with epoxy groups, ensuresthat a complete phase separation does not occur during fusion and curingof the coating powder. However, there are microdomains of epoxy andrubber.

In an alternative embodiment, a core/shell resin is used in which anacrylic rubber resin forms the core and the epoxy resin, preferably abisphenol A epoxy resin, forms the shell. Again, chemical bondingbetween carboxylic functionality of the acrylic rubber resin of the coreand the epoxy resin of the shell prevents phase separation during fusionand curing of the coating powder formed using the core/shell resin. Suchacrylic rubber modified epoxies are described, for example, in PolymerReprints, 32(3), pp. 358-9 by H-J Sue and E. I. Garcia-Melfin.

In another embodiment thermosetting epoxy resins may include either across-linking agent, such as a polyhydroxyl compound or a cure catalystto effect auto-cross-linking of the epoxy resin. For example, the epoxyresin is cured with a polyhydroxyl functionality having a relativelyhigh hydroxy equivalent weight, i.e., at least about 200 up to about500, preferably at least about 300. The relatively high hydroxyequivalent weight of the cross-linking agent ensures relatively longchain length between OH groups, which chain lengths provide flexibilityto the cured coating, helping to render the coatings chip-resistant.Suitable curing agents useful in the practice of this invention areexemplified by phenolic curing agents, such as a bisphenol A end cappeddiglycidyl ether of bisphenol A, which is the reaction product of adiglycidyl ether of bisphenol A and bisphenol A and polyester resinswith free carboxylic acid groups that are known to form “Hybrid” powdercoatings. Examples of preferred phenolic curing agents for the epoxyresin component include those sold under the trademarks D.E.H.™87 andD.E.H.™85 (Dow Chemical Co.), both of which are believed to be bisphenolA end capped diglycidyl ethers of bisphenol A. Other classes of phenolichardeners can be used as well such as phenol- and cresol-novolac curingagents sold by Dow Chemical Co. Hexion Specialty Chemicals.

Other epoxy crosslinking agents include, for example:

-   -   amines, including multifunctional aliphatic or aromatic primary        or secondary amines, such as dicyandiamide, diaminodiphenyl        sulfone;    -   tertiary amines which promote self cross-linking such as DMP 30        (Dow Chemical Co.);    -   boron trihalides and salts thereof such as the monoethanolamine        salt of boron trifluoride;    -   Organic acid salts such as VESTAGON™B55 and VESTAGON™B68        (Degussa Corp.);    -   di and poly anhydrides such as benzophenonetetracarboxylic        dianhydride (BTDA);    -   di and poly phenols such as methylene disalicylic acid; and,    -   imidazoles, substituted imidazoles and epoxy imidazole adducts        such as 2-methyl imidazole or DEH 40 (Dow Chemical Co.).

The powder composition of the present invention is a resin-basedcomposition that includes from 5% to 70%, by weight based on powdercomposition weight, of a corrosion-inhibiting pigment. Thecorrosion-inhibiting pigment may be, for example, at least one of:

-   -   simple molybdates such as zinc molybdate, strontium molybdate        and complex molybdates such as calcium zinc molybdate, calcium        zinc phosphomolybdate (eg., MOLYWHITE™ MZAP);    -   simple chromates such as zinc chromate, barium chromate,        strontium chromate, magnesium chromate, calcium chromate and        complex chromates such as lead silico chromate, zinc tetraoxy        chromate;    -   metal phosphides such as iron phosphide (e.g. FERROPHOS™ iron        phosphide, OCCIDENTAL CHEMICAL CORP., Dallas, Tex.);    -   silicates such as zinc phosphosilicate and calcium borosilicate;        and    -   simple phosphates such as iron phosphate, zinc phosphate, zinc        pyrophosphate, calcium hydrogen phosphate and complex phosphates        such as zinc borate orthophosphate, strontium aluminum        polyphosphate, zinc aluminum polyphosphate, zinc aluminum        molybdenum orthophosphate, zinc aluminum orthophosphate.

The pigments may be present in their basic form, may be organicmodified, and may be present as the hydrate. Other descriptions ofsuitable corrosion-inhibiting pigments appear in U.S. Pat. No. 3,884,705and are summarized by G.B. Rothenberg in Paint Additives, Noyes DataCorp, 1978, pp 175-177. U.S. Pat. No. 7,244,780 also disclosescorrosion-inhibiting pigments that include “a source of stabilizinganions, advantageously phosphate ions, capable of dissolving in thepresence of water”.

Zinc phosphate herein is contemplated to include (a) Zinc phosphate di-or tetra-hydrate, preferably in the form of spheroidal particles asdescribed in U.S. Pat. No. 5,137,567 (an example of zinc phosphatedihydrate being the material available under the trade name DELAPHOS™ 2Mand a further example of a zinc phosphate being the available under thetrade name HISPAFOS™ SP, comprising spheric particles of narrow particlesize distribution); (b) Spheroidal zinc phosphate as a crystalline phasein admixture with an amorphous phase comprising Fe(II) phosphate andFe(III) phosphate. Further information concerning such materials may befound in U.S. Pat. No. 5,030,285; and (c) Zinc phosphate (preferably inspheroidal form) modified with zinc molybdate (such as ACTIROX™106;Microfine Minerals Ltd.)

The powder composition optionally includes from 0% to 65%, by weightbased on powder composition weight, zinc; typically the zinc is inpowder or flake form. Preferably the powder composition includes aminimal amount of zinc; more preferably the powder composition is freefrom zinc.

The powder composition of the present invention is “substantially freefrom pigment providing a metallic effect”, which means that the totalproportion of metallic pigment(s) incorporated in the powder coatingcomposition shall be less than 0.1 by weight (based on the weight of thecomposition without the metallic pigment(s)); preferably no metallicpigment is included in the powder composition. By “a pigment providing ametallic effect” herein is meant a metallic pigment typically in flakeform such as, for example, aluminium or an aluminium alloy or anothermetal or alloy, for example, stainless steel, copper, tin, bronze orbrass typically used to produce various metallic effects including thosereferred to as “metallic”, “effect”, “lustre”, or “glamour” finishes.

The metallic pigment may be an uncoated or coated material. Examples ofcoated materials include pigments coated with silica or another inertinorganic material for greater chemical resistance and durability.Alternatively, the pigment may be coated with a plastics material forsimilar purposes, for example, an acrylic, PTFE or thermosettingplastics material, or may be provided in a polymer or plasticizer whichis compatible with the film-forming binder of the powder coatingcomposition. As a further possibility, the metallic pigment may becoated with a coloring agent such as a metal oxide pigment such as, forexample, iron oxide, to provide special color effects.

Powder compositions used to provide the chip-resistant andcorrosion-resistant coatings of the present invention are produced inthe usual manner. The components are blended, and then aremelt-compounded with heating above the melting point of the resin for ashort time, e.g., 30 to 90 sec., so that no significant curing occurs.The molten compound is extruded, and after extrusion, the composition israpidly cooled. The composition is then ground and, as necessary, theparticulates sorted according to size. For electrostatic coating, theparticles are generally in the 5 to 100 micron size range with a majorportion generally being in the 20 to 40 micron size range. Largerparticulates are useful for fluidized bed coating operations.

In the method for coating a substrate of the present invention thepowder composition of the present invention is applied to the substrateand heated to fuse and cure the applied composition. In one embodimentthe substrate is a metal substrate, typically a steel substrate, whereinthe powder composition may be may be used, for example, as a pipecoating, rebar coating, or a coating for agricultural or constructionequipment. In another embodiment the substrate is a high tensile steelsubstrate such as is suitable for use, for example, in coil springs inthe transportation industry. Herein, high tensile steel is defined ashaving MPa (megapascal (N/m²) ranging from 1800 Mpa to 2100 Mpa orabove; this includes super high tensile steel from 1950 Mpa to 2100 Mpaor above. Steel substrates herein are contemplated to include pretreatedsteel substrates, including treatments of, for example, zinc phosphate,iron phosphate, and dry in place pretreatment technology. The powdercomposition is typically heated at a temperature of greater than 149° C.(300° F.) for a time sufficient to fuse and substantially cure thecoating such as, for example, by placing into an electric aircirculating oven maintained at 160° C. (320° F.) for 20 minutes for acured film thickness of 50 to 101 μm (2.0-4.0 mils). It is understoodthat thermoplastic resins do not include a cure mechanism and thereforewill only fuse under heating.

In the method for coating a substrate of the present invention thepowder composition may be applied as a single coat, with sufficient filmthickness for chip resistance protection. In an alternative embodimentthe powder composition may be applied as a single foamed coat, the foamhaving been engendered by the use of a separate foaming agent or by thetemperature-dependent inherent foaming of certain phosphate and relatedconstituents such as, for example, zinc phosphate. Optionally, thepowder composition may incorporate reinforcing technology, that is, thecomposition may include carbon fibers, slip agents, barium sulfate,calcium carbonate, wollastonite, or any materials that will reinforcethe coating to enhance chip resistance.

In an alternative method of the present invention a two coat method maybe employed. In such embodiments a first coat (base coat) is applied andthe basecoat may be partially or fully cured. Then a subsequent secondcoat (top coat) is applied to the base coat and the coats are fused andcured. Either of the first coat, the second coat, or both first andsecond coats, independently, is formed from the powder composition ofthe present invention. Either of the first coat, the second coat, orboth first and second coats may independently be foamed coats asdescribed hereinabove. Either of the first coat, the second coat, orboth first and second coats may independently include carbon fibers,slip agents, barium sulfate, calcium carbonate, wollastonite, or anymaterials that will reinforce the coating to enhance chip resistance.

The introduction of cellular foam structures is not limited to theorganic portion of the protective system. For example, the steelcleaning and “pretreatment” or passivation step may introduce and orinclude foam forming components which generate a cellular structurewithin the pretreatment layer or the organic layer above it as evolvedgases percolate through the film during heating. Examples of such gasgenerators are azo compounds, well known in the industry. Such foam mayalso be produced by simple decomposition or dehydration of thepretreatment chemicals themselves. Zinc phosphate (hopeite and/orphosphyllite), for example, having been deposited on cold rolled steelpanels, has been shown to foam by heating to approximately 200° C.

The coated substrate of the present invention bears a coating includinga resin and from 5% to 70%, by weight, based on powder compositionweight, of a corrosion-inhibiting pigment, optionally further includingfrom 0% to 65%, by weight based on powder composition weight, zinc, thecomposition being substantially free from pigment providing a metalliceffect. It is formed by the above-described method of the presentinvention.

EXAMPLE 1 Formation of Powder Compositions and Application to Substrates

TABLE 1.1A Powder compositions Zinc Phosphate-Containing Base Coatcompositions Example No. 1-1 1-2 1-3 1-4 2-1 5% 10% 20% 30% 44%Zn3(PO4)2 Zn3(PO4)2 Zn3(PO4)2 Zn3(PO4)2 Zn3(PO4)2 Epoxy resin A 92 92 9292 92 Imidazole 3 3 3 3 3 adduct B Carbon black 3 3 3 3 3 pigmentHydroxy 20.8 20.8 20.8 20.8 20.8 compound C Epoxy resin D 8 8 8 8 8 ZincDust 0 0 0 0 0 Zinc Phosphate 6.7 14.5 32 54 100 Fumed silica 0.30%0.30% 0.30% 0.30% 0.30% Other Corrosion-Inhibiting Base Coatcompositions 3-1 3-2 3-3 3-4 3-5 Epoxy resin A¹ 92 92 92 92 92 Imidazoleadduct 3 3 3 3 3 B² Carbon black 3 3 3 3 3 pigment Hydroxy 20.8 20.820.8 20.8 20.8 compound C³ Epoxy resin D⁴ 8 8 8 8 8 Zinc Dust 237.5 225200 175 150 Zinc Phosphate 0 0 0 0 0 FERROPHOS ™ 12.5 25 50 75 100Strontium Zinc 0 0 0 0 0 Phosphosilicate Calcium 0 0 0 0 0 BorosilicateFumed Silica 0.30% 0.30% 0.30% 0.30% 0.30% ¹Diglycidyl ether ofbisphenol A epoxy resin with a weight per epoxide between 935 and 1175.²Imidazole adduct with a diglycidyl ether of bisphenol A epoxy resin.³Bisphenol A end capped diglycidyl ether of bisphenol A with a hydroxylequivalent weight between 370 and 400. ⁴Master Batch epoxy resincontaining 90 wt % of a diglycidyl ether of bisphenol A epoxy resin witha weight per epoxide between 795 and 895 and 10 wt % of acrylic flowmodifier.

TABLE 1.1B Powder compositions Zinc Phosphate-Containing Base Coatcompositions Example No. 2-2 44% Zn3(PO4)2 2-3 2-4 2-5 2-6 Control Epoxyresin A 92 92 92 92 92 92 Imidazole adduct B 3 3 3 3 3 3 Carbon black 33 3 3 3 3 pigment Hydroxy 20.8 20.8 20.8 20.8 20.8 20.8 compound C Epoxyresin D 8 8 8 8 8 8 Zinc Dust 150 175 200 225 237 250 Zinc Phosphate 10075 50 25 12.5 0 Fumed silica 0.30% 0.30% 0.30% 0.30% 0.30% 0.30% OtherCorrosion-Inhibiting Base Coat compositions 4-1 4-2 4-3 4-4 Epoxy resinA¹ 92 92 92 92 Imidazole adduct B² 3 3 3 3 Carbon black 3 3 3 3 pigmentHydroxy 20.8 20.8 20.8 20.8 compound C³ Epoxy resin D⁴ 8 8 8 8 Zinc Dust0 0 0 0 Zinc Phosphate 0 0 0 0 FERROPHOS ™ 0 0 0 0 Strontium Zinc 3.2 140 0 Phosphosilicate Calcium Borosilicate 0 0 6.7 22.4 Fumed Silica 0.30%0.30% 0.30% 0.30% ¹Diglycidyl ether of bisphenol A epoxy resin with aweight per epoxide between 935 and 1175. ²Imidazole adduct with adiglycidyl ether of bisphenol A epoxy resin. ³Bisphenol A end cappeddiglycidyl ether of bisphenol A with a hydroxyl equivalent weightbetween 370 and 400. ⁴Master Batch epoxy resin containing 90 wt % of adiglycidyl ether of bisphenol A epoxy resin with a weight per epoxidebetween 795 and 895 and 10 wt % of acrylic flow modifier.

Powder samples were electrostatically applied onto 7.68 cm×12.8 cm×0.082cm (3 inch×5 inch×0.032 inch) steel panels. Panels were supplied by ACTLaboratories, Inc., B-958, P-60 (Zinc Phosphate/Non Chrome Rinse).Powder coated panels were placed into an electric air circulating ovenmaintained at 160° C. (320° F.) for 20 minutes. Cured film thickness was50 to 101 μm (2.0-4.0 mils).

EXAMPLE 2 Evaluation of Powder Coated Panels

Each of the coated panels exhibited a direct/reverse impact rating of1.84 kg-m (160 in-lb)/1.84 kg-m (160 in-lb).

The coated panels of Example 1 were scribed with an ‘X’ and placed in aSalt Fog Cabinet According to ASTM Method B 117. At intervals panelswere removed from the cabinet and scraped with a dull knife,perpendicularly to scribed lines. Maximum undercutting (corrosion) wasmeasured in inches outwardly from the scribe line. Panels were typicallyexposed for 3000 to 4000 hours.

As shown in Table 2.1, below, the powder composition-coated panels ofthe present invention, Examples 1-1, 1-2, 1-3, 1-4, and 2-1, exhibited auseful level of impact resistance and salt spray corrosion resistance.

TABLE 2.1 Creepback from X-scribe during ASTM B 117 Salt Spray ExposureExample No. Comparative 1-1 1-2 1-3 1-4 2-1 HOURS 66% Zn 5% 10% 20% 30%44% EXPOSED Dust Zn3(PO4)2 Zn3(PO4)2 Zn3(PO4)2 Zn3(PO4)2 Zn3(PO4)2 192NC NC NC NC NC NC 384 NC NC NC NC NC NC 552 NC NC NC NC NC NC 672 NC NCNC NC NC NC 840 NC NC NC NC NC NC 1008 NC < 1/32″ < 1/32″ < 1/32″ <1/32′ < 1/32″ 1176 NC NC < 1/32″ < 1/32″ < 1/32′ NC 1344 NC < 1/32″ <1/32″ < 1/32″ < 1/32′ < 1/32″ 1512 NC < 1/32″ < 1/32″ < 1/32″ < 1/32′ <1/32″ 1680 < 1/32″ < 1/32″ < 1/32″ < 1/32″ < 1/32′ < 1/32″ 1848 < 1/32″< 1/32″    1/32″    1/32″ < 1/32′ < 1/32″ 2016 < 1/32″    1/32″    1/32″   1/32″    1/32″    1/32″ 2184 < 1/32″    1/32″    1/32″    1/32″ <1/32″ < 1/32″ 2352 < 1/32″    1/32″    1/32″    1/32″    1/32′ < 1/32″2520 < 1/32″ > 1/32″    1/16″    1/32″ > 1/32″ < 1/32″ 2688 < 1/32″   1/16″    1/16″    1/16″    1/16′    1/32″ 2856 < 1/32″    1/16″ > 1/16″   1/16″    1/16′    1/16″ 3024 < 1/32″    1/16″    3/32″    3/32″   3/32″    1/16″ 3192 < 1/32″    1/16″    3/32″    3/32″    3/32″    1/16″3360    1/32″    3/32″   ⅛″ > 3/32″    3/32″    1/16″ 3528    1/32″   3/32″   ⅛″   ⅛″    3/32″    1/16″ 3696    1/32″    3/32″   ⅛″   ⅛″   3/32″    1/16″ 3864    1/32″   ⅛″    3/16″   ⅛″   ⅛″    1/16″ 4056   1/16″   ⅛″ >¼″    3/16″    3/16″    3/32″

1. A powder composition comprising a resin and from 5% to 70%, by weightbased on powder composition weight, of a corrosion-inhibiting pigment,said composition being substantially free from pigment providing ametallic effect.
 2. The composition according to claim 1 furthercomprising from 0% to 65%, by weight based on powder composition weight,zinc.
 3. The composition according to claim 1 further comprises at leastone technology selected from the group consisting of toughening,foaming, and reinforcing.
 4. A method for coating a substratecomprising: forming a powder composition comprising a resin and from 5%to 70%, by weight based on powder composition weight, of acorrosion-inhibiting pigment, said composition being substantially freefrom pigment providing a metallic effect; applying said powdercomposition to said substrate; and heating said applied powdercomposition to fuse and cure said composition.
 5. The method accordingto claim 3 wherein said powder composition further comprises from 0% to65%, by weight based on powder composition weight, zinc.
 6. The methodaccording to claim 3 wherein said powder composition further comprisesat least one technology selected from the group consisting oftoughening, foaming, and reinforcing.
 7. A method for coating asubstrate comprising: forming a first powder composition comprising aresin and from 0% to 70%, by weight based on powder composition weight,of a corrosion-inhibiting pigment, said first powder composition beingsubstantially free from pigment providing a metallic effect; applyingsaid first powder composition to said substrate; forming a second powdercomposition comprising a resin and from 5% to 70%, by weight based onpowder composition weight, of a corrosion-inhibiting pigment, saidcomposition being substantially free from pigment providing a metalliceffect; applying said second powder composition to said substrate coatedwith said first powder composition; and heating said applied powdercompositions to fuse and cure said compositions.
 8. The method accordingto claim 7 wherein said first and said second powder composition,independently, further comprise from 0% to 65%, by weight based onpowder composition weight, zinc.
 9. A coated substrate comprising saidsubstrate bearing a coating comprising a resin and from 5% to 70%, byweight based on powder composition weight, of a corrosion-inhibitingpigment, said composition being substantially free from pigmentproviding a metallic effect.
 10. The coated substrate of claim 9 whereinsaid powder composition further comprises from 0% to 65%, by weightbased on powder composition weight, zinc.